Heat exchangers are commonly used in order to transfer energy from one fluid to another through a solid surface. Typical heat exchangers feature tubes, ducts or paths (hereinafter tubes) in which a first fluid circulates as a result of action from a pump, pressure source or the like. A second fluid is in contact with an exterior surface of the tube so as to exchange energy with the first fluid circulating in the tubes. The tube may be shaped in a coil, provided with fins or the like, depending on the heat-exchanger configuration (e.g., shell and tube, heat-exchanger coil, radiator, etc.)
One of the issues with such heat exchangers is that the tubes are costly in terms of material and space. Moreover, because of the friction of the first fluid against the surface of the tube, there is a substantial fluid pressure drop in the heat exchanger. Accordingly, a substantial amount of energy is required to maintain a suitable flow of the first fluid in heat exchangers.